New technology would limit invasion of privacy posed by CCTVs

Published 2 February 2009

CCTVs proliferate to every corner, and worries grow about eroding privacy; a scientist offers a solution: face-blurring technology which would prevent the distribution on one’s image captured on CCTV without the authorization of those who sign up for the service

Karl Marx said that history is like the weather: Everyone talks about it but few do anything to change it. It is the same with CCTVs: Everyone talks about how these ever-more-ubiquitous devices erode our privacy, but few do anything to change this trend. The notable exception: Jack Brassil, a computer scientist at Hewlett-Packard’s laboratory in Princeton, New Jersey, who is testing a technology called Cloak which aims to limit the extent of privacy invasions. “Rather than prohibit surveillance, our system seeks to discourage surveillers distributing video without the authorization of the surveilled,” he says.

Paul Marks writes that Cloak has two key requirements. First, CCTV users, such as municipal councils and businesses, would have to sign up to a system that electronically obscures the faces of people who do not want their pictures to be published in video footage that is passed to others. The list of such people would be akin to the national “do-not-call” lists designed to prevent telemarketers from cold-calling your phone, Brassil says.

Second, the person opting in to Cloak needs to carry a “privacy enabling device” — most conveniently a phone with GPS capability. This device wirelessly beams the user’s position and velocity to a central server which forwards the data to the CCTVs control center. Image processing software then uses the subject’s trajectory to identify and obscure their face in the CCTV footage if it is to be distributed. In Hewlett-Packard’s simulations, the technology is workable, even in dense crowds.

The idea raises broad societal and legal questions. “I don’t think its objectives are right at all,” says privacy analyst Ian Brown of the Oxford Internet Institute in the United Kingdom. “People shouldn’t have to opt in to get privacy protection. And this system actively invades your privacy because it tells the service where you are at all times.”

Brassil concedes that his proposed solution may not suit everyone, but says the important point is the discussion of privacy. Brown also notes that there are transatlantic legal differences to contend with. In Europe, data protection laws prevent surveillance videos being passed on while only a few states in the United States have such legislation. He says another way forward is to encourage engineers to design privacy into technologies from the start.

Brown will have his work cut out, says Brassil, who is to publish his work as part of a book on video surveillance later this year. “Technology is advancing far faster than our ability to understand its privacy implications,” he says.